[ale] iptraf / bandwidth monitoring

[me at seebq.com (Charles Brian Quinn)]

Just a semi-linux related, semi-off-topic quick question for those who 
work in/for/around data centers.

For dedicated servers or collocated servers in data centers, what tools 
are used to monitor bandwidth usage?

Let's just say, for instance that I have a dedicated server with a 200 
GB transfer (and $0.89 per GB thereafter) included in the "dedicated 
hosting" plan.  A friend puts up his portfolio on said server and it is 
immensely popular.  4 days later and 35 GB of web traffic transfers 
(webstats show), not to mention other ssh/rsync traffic, I'm starting to 
worry about going over that 200 GB transfer limit, having never come 
close ever before.

How is web traffic versus rsync/ssh versus dns versus any IP traffic 
monitored, and is there any way on the (linux-based) server itself to do 
this type of passive monitoring/logging (iptraf, maybe), to compare to 
the provider's when I get the bill for the next month?

Thanks,
-- 
Charles Brian Quinn
www.seebq.com